An in-line version of the popular Vernalift, this muffler was designed for sailboat auxiliary propulsion engines installed near or below the water line. If the engine exhaust manifold is near or below the waterline, a siphon break must be installed in the water supply line to prevent continued water flow after the engine is shut down. When several body sizes are available, choose the largest that will fit the available space. The increased volume will help ensure that residual water doesn't enter the engine after shutdown; the longer the exhaust system hoses, the more important this is.• Applications: powerboat, sailboat and generator engines• Fuel type: gas or diesel• Installation: above or below waterline, close to centerline• Sound rating: better